Torque Converter Question

[gag1025]

My 1953 Chevy truck has a 350 engine with a mild cam (I bought the truck with the engine installed so I have no information on the cam) The rear differential is a1976 Camaro 10 Bolt with a 2:56 ratio. At low speed the carburetor (Holley 4150 570ccfm) loads up. Once you accelerate it is OK. I was told that I need to replace the torque converter to correct the problem. My question is how do I determine which torque converter to replace it with. I am running a Chevy turbo 350 transmission. All ideas will be greatly appreciated.